1. Field of the Invention
The present invention relates to an organic metal complex having absorption in an infrared region and an infrared-absorbing dye containing the same. Specifically, it relates to an infrared-absorbing dye material which can be used as e.g., a dye for an infrared absorption filter, a dye for heat ray shielding, a dye for a light shielding film, a dye for an optical recording material, a dye for data coding, a dye for a laser printer, a singlet oxygen quencher or a color fading preventive agent. Further, it relates to an infrared absorption filter containing such a dye, which is excellent in the near infrared absorption performance, heat ray absorption performance, visible light transmission and light resistance and thus useful as a filter to shield infrared rays, specifically an infrared absorption filter which is useful as a filter for an image display device or a heat ray absorption filter, such as a filter for a plasma display panel or an infrared filter for a digital camera.
2. Description of the Background
Generally, a near infrared absorption filter containing a near infrared-absorbing dye, is well known, and as applications therefor, sunglasses, glasses for welding, windows of buildings, automobiles, trains or airplanes, or an optical reader for reading out information, may, for example, be mentioned.
Recently, a filter containing an infrared-absorbing dye capable of absorbing near infrared rays, has become in demand also as a filter for a plasma display panel (hereinafter referred to as “PDP”), since PDP which has attracted an attention as a large sized thin type wall-hung TV, generates near infrared rays, which in turn affect nearby electronic equipments such as cordless phones or video players employing near infrared ray remote control systems to create malfunctions.
To meet such a demand, JP-B-2-4881 proposes an optical filter made of a thermoplastic resin having a benzene dithiol type metal complex incorporated. Further, JP-B-6-38124 proposes a near infrared absorption film or plate containing at least one member among an anthraquinone compound and a naphthalocyanine type compound having a metal atom coordinated at the center. JP-A-4-174402 proposes an infrared absorption filter obtained by further polymerizing a curing a synthetic resin composition containing an aluminum compound. Further, in recent years, as a filter for plasma display, JP-A-9-230134 proposes a filter for plasma display containing a dithiol type metal complex, and JP-A-10-78509 proposes a filter for plasma display containing a phthalocyanine dye.
Further, JP-A-63-112592 discloses an aminothiophenolate type metal complex dye, and as its application, a dye for an infrared absorption filter is mentioned. However, such a dye is inferior in the light resistance and has a problem with respect to the visible light transmittance, and thus it is not practically adequate.
Further, in recent years, as an aminothiophenolate type metal complex, a metal complex having a ligand of a type wherein N atom and N atom are connected via carbon, has been reported by Kushi et al, Bull. Chem. Soc. Jpn., 70(7)(1997)1599-1606. Such a dye shows intense absorption in a near infrared region, but in the UV-Vis spectrum in a solution, it is in equilibrium with a precursor showing absorption in a visible region, thus showing absorption in both the near infrared region and the visible region, whereby there is a problem that when it is processed into a product by using a solvent, it has absorption in the visible region, and the transmittance in the visible region decreases.